U.S. patent number 8,057,500 [Application Number 12/184,648] was granted by the patent office on 2011-11-15 for flexible inner member having a flexible region comprising a cut with convoluted path areas.
This patent grant is currently assigned to B&M Precision, Inc.. Invention is credited to Miroslav Mitusina.
United States Patent |
8,057,500 |
Mitusina |
November 15, 2011 |
Flexible inner member having a flexible region comprising a cut
with convoluted path areas
Abstract
A flexible inner member for rotation within an angled outer
tubular member of a rotary tissue cutting instrument to cut
anatomical tissue includes a flexible region for conforming to the
configuration of an angled region of the outer tubular member. The
flexible region comprises a cut having convoluted path areas formed
through a cylindrical wall of a tubular body of the inner member.
The convoluted path areas are rotationally spaced on the tubular
body in alternating sequence with connecting path segments of the
cut. The cut follows a convoluted path in the convoluted path areas
forming the wall of the tubular body into a pair of complementary,
mating hook formations of opposed curvature. The connecting path
segments extend rotationally along the tubular body between the
convoluted path areas.
Inventors: |
Mitusina; Miroslav (Ruskin,
FL) |
Assignee: |
B&M Precision, Inc.
(Ruskin, FL)
|
Family
ID: |
41609113 |
Appl.
No.: |
12/184,648 |
Filed: |
August 1, 2008 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100030217 A1 |
Feb 4, 2010 |
|
Current U.S.
Class: |
606/180; 606/79;
606/170 |
Current CPC
Class: |
A61B
17/32002 (20130101); A61B 2017/320032 (20130101) |
Current International
Class: |
A61B
17/14 (20060101) |
Field of
Search: |
;606/167,170,180,79
;623/1.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Houston; Elizabeth
Assistant Examiner: Webb; Sarah
Claims
What is claimed is:
1. An angled rotary tissue cutting instrument for cutting
anatomical tissue, comprising an elongate angled outer tubular
member having a distal end, a longitudinal internal passage, an
open proximal end communicating with said passage, an angled region
between said distal end and said proximal end, and an opening in
said distal end communicating with said passage; and a flexible
inner member for being rotatably disposed within said outer tubular
member, said inner member having a distal end, a proximal end, a
tubular body between said distal end of said inner member and said
proximal end of said inner member, a cutting element at said distal
end of said inner member, said cutting element being exposed from
said opening to cut anatomical tissue when said inner member is
rotatably disposed within said outer tubular member, and a flexible
region for being disposed within said angled region to transmit
torque to rotate said cutting element while conforming to the
configuration of said angled region when said inner member is
rotated within said outer tubular member, said tubular body having
a central longitudinal axis and a cylindrical wall with an external
diameter surface, an internal diameter surface, and a wall
thickness between said external diameter surface and said internal
diameter surface, said flexible region consisting of a convoluted
cut in said tubular body extending entirely through said wall
thickness, said convoluted cut having a single starting end on said
tubular body and a single terminating end on said tubular body,
said convoluted cut being continuous from said starting end to said
terminating end, said convoluted cut following a winding path
extending longitudinally along said tubular body and extending in a
rotational direction about said central longitudinal axis in a
forward direction of said convoluted cut from said starting end to
said terminating end, said convoluted cut consisting of a plurality
of convoluted path areas rotationally spaced about said central
longitudinal axis along said winding path between said starting end
and said terminating end and a plurality of connecting path
segments alternating individually with said convoluted path areas
such that a single connecting path segment is disposed between
successive convoluted path areas in said forward direction, said
connecting path segments extending in said rotational direction
along said tubular body, said convoluted cut following a convoluted
path in said convoluted path areas in said forward direction of
said cut comprising a first major curve of concave curvature
extending from a next preceding one of said connecting path
segments in a lateral direction away from said next preceding one
of said connecting path segments, a first minor curve of concave
curvature reverse from said curvature of said first major curve
extending from said first major curve in an opposite lateral
direction toward said next preceding one of said connecting path
segments, a second minor curve of concave curvature reverse from
said curvature of said first minor curve extending from said first
minor curve in said opposite lateral direction, and a second major
curve of concave curvature reverse from said curvature of said
second minor curve extending from said second minor curve in said
lateral direction to a next succeeding one of said connecting path
segments, said first minor curve being within said second major
curve and being spaced from said second major curve in a direction
radial to said second major curve, said second minor curve being
within said first major curve and being spaced from said first
major curve in a direction radial to said first major curve, said
convoluted cut in said tubular body imparting sufficient strength
and rigidity to said flexible region for said flexible region to
transmit torque to rotate said cutting element to cut anatomical
tissue.
2. The angled rotary tissue cutting instrument recited in claim 1
wherein said major curves have a radius of curvature, and said
minor curves have a radius of curvature about 60% of said radius of
curvature of said major curves.
3. The angled rotary tissue cutting instrument recited in claim 1
wherein said connecting path segments are all disposed at the same
acute angle to a plane perpendicular to said central longitudinal
axis of said tubular body.
4. The angled rotary tissue cutting instrument recited in claim 3
wherein said connecting path segments are parallel to one another
along said tubular body.
5. The angled rotary tissue cutting instrument recited in claim 1
wherein said lateral direction and said opposite lateral direction
are transverse to said next preceding one of said connecting path
segments and to said next succeeding one of said connecting path
segments.
6. The angled rotary tissue cutting instrument recited in claim 5
wherein said lateral direction is toward said distal end of said
inner member and said opposite lateral direction is toward said
proximal end of said inner member.
7. The angled rotary tissue cutting instrument recited in claim 6
wherein said lateral direction is toward said terminating end of
said convoluted cut and said opposite lateral direction is toward
said starting end of said convoluted cut.
8. An angled rotary tissue cutting instrument for cutting
anatomical tissue, comprising an elongate angled outer tubular
member having a distal end, a longitudinal internal passage, an
open proximal end communicating with said passage, an angled region
between said distal end and said proximal end, and an opening in
said distal end communicating with said passage; and a flexible
inner member for being rotatably disposed within said outer tubular
member, said inner member having a distal end, a proximal end, a
tubular body between said distal end of said inner member and said
proximal end of said inner member, a cutting element at said distal
end of said inner member, said cutting element being exposed from
said opening to cut anatomical tissue when said inner member is
rotatably disposed within said outer tubular member, and a flexible
region for being disposed within said angled region to transmit
torque to rotate said cutting element while conforming to the
configuration of said angled region when said inner member is
rotated within said outer tubular member, said tubular body having
a central longitudinal axis and a cylindrical wall with an external
diameter surface, an internal diameter surface, and a wall
thickness between said external diameter surface and said internal
diameter surface, said flexible region consisting of a convoluted
cut in said tubular body extending entirely through said wall
thickness, said convoluted cut having a single starting end on said
tubular body and a single terminating end on said tubular body,
said convoluted cut being continuous from said starting end to said
terminating end said convoluted cut following a winding path
extending longitudinally along said tubular body and extending in a
rotational direction about said central longitudinal axis in a
forward direction of said convoluted cut from said starting end to
said terminating end, said convoluted cut consisting of a plurality
of convoluted path areas rotationally spaced about said central
longitudinal axis along said winding path between said starting end
and said terminating end and a plurality of connecting path
segments alternating with said convoluted path areas, said
connecting path segments extending in said rotational direction
along said tubular body and being devoid of said convoluted path
areas, said convoluted cut following a convoluted path in said
convoluted path areas consisting of a first major curve of concave
curvature having an inner side continuous with a next preceding one
of said connecting path segments and having an outer side spaced
from said next preceding one of said connecting path segments, a
first minor curve of reverse concave curvature to said first major
curve and having an outer side continuous with said outer side of
said first major curve and having an inner side between said outer
side of said first minor curve and said next preceding one of said
connecting path segments, a second minor curve of concave curvature
curving in the same direction as said first major curve and being
within said first major curve in spaced relation to said first
major curve, said second minor curve having an inner side
continuous with said inner side of said first minor curve and
having an outer side between said inner side of said second minor
curve and said next preceding one of said connecting path segments,
and a second major curve of concave curvature curving in the same
direction as said first minor curve and having an outer side
continuous with said outer side of said second minor curve and
having an inner side continuous with a next succeeding one of said
connecting path segments, said first minor curve being within said
second major curve in spaced relation to said second major curve,
said convoluted cut in said tubular body imparting sufficient
strength and rigidity to said flexible region for said flexible
region to transmit torque to rotate said cutting element to cut
anatomical tissue.
9. The angled rotary tissue cutting instrument recited in claim 8
wherein said connecting path segments are all disposed at the same
acute angle with a plane perpendicular to said central longitudinal
axis of said tubular body and extend in said forward direction of
said cut with a slant toward said proximal end of said inner
member.
10. The angled rotary tissue cutting instrument recited in claim 8
wherein said convoluted path areas have an entering convoluted path
portion formed by said first major curve and said first minor
curve, and an exiting convoluted path portion formed by said second
minor curve and said second major curve, and said exiting
convoluted path portion is an inverted mirror image of said
entering convoluted path portion.
11. The angled rotary tissue cutting instrument recited in claim 8
wherein said first and second major curves have a radius of
curvature of about 0.02 inch and said first and second minor curves
have a radius of curvature of about 0.012 inch.
12. The angled rotary tissue cutting instrument recited in claim 11
wherein said convoluted path portions each have a width in a
direction parallel to said central longitudinal axis of said
tubular body of about 0.04 inch.
13. An angled rotary tissue cutting instrument for cutting
anatomical tissue, comprising an elongate outer tubular member
having a distal end, a longitudinal internal passage, an open
proximal end communicating with said passage, an angled region
between said distal end and said proximal end, and an opening in
said distal end communicating with said passage; and a flexible
inner member for being rotatably disposed within said outer tubular
member, said inner member having a distal end, a proximal end, a
tubular body between said distal end of said inner member and said
proximal end of said inner member, a cutting element at said distal
end of said inner member, said cutting element being exposed from
said opening to cut anatomical tissue when said inner member is
rotatably disposed within said outer tubular member, and a flexible
region for being disposed within said angled region to transmit
torque to rotate said cutting element while conforming to the
configuration of said angled region when said inner member is
rotated within said outer tubular member, said tubular body having
a central longitudinal axis and a cylindrical wall with an external
diameter surface, an internal diameter surface, and a wall
thickness between said external diameter surface and said internal
diameter surface, said flexible region consisting of a convoluted
cut in said tubular body extending entirely through said wall
thickness, said convoluted cut having a single starting end on said
tubular body and a single terminating end on said tubular body,
said convoluted cut following a winding path extending
longitudinally along said tubular body and extending in a
rotational direction about said central longitudinal axis in a
forward direction of said convoluted cut from said starting end to
said terminating end, said convoluted cut consisting of a plurality
of convoluted path areas rotationally spaced about said central
longitudinal axis along said winding path between said starting end
and said terminating end and a plurality of connecting path
segments alternating with said convoluted path areas, said
convoluted cut being continuous through said convoluted path areas
and following a convoluted configuration in each of said convoluted
path areas forming a single pair of opposed hook formations in said
wall of said tubular body in each of said convoluted path areas,
each of said pairs of opposed hook formations consisting of a first
hook formation of concave curvature and a second hook formation of
concave curvature reverse from said curvature of said first hook
formation, said first and second hook formations of each of said
pairs of opposed hook formations being interengaged with one
another in a complementary, mating fit, each of said pairs of
opposed hook formations being disposed between a next preceding one
of said connecting path segments and a next succeeding one of said
connecting path segments, said connecting path segments extending
in said rotational direction at a non-perpendicular angle to said
central longitudinal axis and being devoid of said hook formations,
said convoluted cut in said tubular body impartinq sufficient
strength and rigidity to said flexible region for said flexible
region to transmit torque to rotate said cutting element to cut
anatomical tissue.
14. The angled rotary tissue cutting instrument recited in claim 13
wherein said convoluted cut is continuous from said starting end to
said terminating end.
15. The angled rotary tissue cutting instrument recited in claim 13
wherein said first hook formations are disposed on a first side of
said convoluted cut and curve with a clockwise rotation in a
direction toward said starting end, and said second hook formations
are disposed on a second side of said convoluted cut opposite from
said first hook formations and curve with a clockwise rotation
toward said terminating end.
16. The angled rotary tissue cutting instrument recited in claim 15
wherein said first hook formations include a neck integral with
said cylindrical wall of said tubular body on said first side of
said convoluted cut and a concavely curving body extending from
said neck to a rounded tip, said second hook formations are an
inverted mirror image of said first hook formations and include a
neck integral with said cylindrical wall of said tubular body on
said second side of said convoluted cut and a concavely curving
body extending from said neck to a rounded tip, said tips of said
first hook formations mating with said concave curvature of said
second hook formations and said tips of said second hook formations
mating with said concave curvature of said first hook
formations.
17. The angled rotary tissue cutting instrument recited in claim 16
wherein said curving bodies of said first hook formations have a
longer outer side edge of concave curvature and a shorter inner
side edge of concave curvature in the same direction as said
concave curvature of said outer side edge, said curving bodies of
said second hook formations have a longer outer side edge of
concave curvature reverse from said concave curvature of said outer
side edge of said first hook formations, and a shorter inner side
edge of concave curvature in the same direction as said concave
curvature of said outer side edge of said second hook
formations.
18. The angled rotary tissue cutting instrument recited in claim 17
wherein said outer side edges have a radius of curvature of 0.02
inch and said inner side edges have a radius of curvature of 0.012
inch.
19. The angled rotary tissue cutting instrument recited in claim 18
wherein said first and second hook formations each have a width in
a direction parallel to said central longitudinal axis of 0.04
inch.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains generally to flexible inner members
rotatably disposed within angled outer tubular members of rotary
surgical tissue cutting instruments wherein the inner member has a
flexible region to transmit torque while conforming to the angled
configuration of the outer tubular member. More particularly, the
present invention pertains to flexible inner members of angled
rotary tissue cutting instruments wherein the flexible region
comprises a cut with convoluted path areas formed in a tubular body
of the inner member.
2. Brief Discussion of the Related Art
Angled rotary tissue cutting instruments have become widely
accepted for use in various surgical procedures to cut anatomical
tissue at a surgical site within a patient's body. Angled rotary
tissue cutting instruments typically comprise an elongate angled
outer tubular member and an elongate flexible inner tubular member
rotatably disposed within the angled outer tubular member. A
cutting element at a distal end of the inner member is exposed from
an opening at a distal end of the outer member to cut anatomical
tissue at the surgical site when the inner member is rotated within
the outer member. The inner member is ordinarily rotated within the
outer member via a powered surgical handpiece coupled to proximal
ends of the outer and inner members, with the handpiece being
maintained externally of the patient's body. The outer tubular
member has one or more angled, curved or bent regions along its
length to provide an angled configuration that facilitates
positioning of the cutting element at the surgical site when the
instrument is introduced in the patient's body, and particularly
when the instrument is introduced through a narrow or small size,
natural or artificially created entry opening in the patient's
body. The inner tubular member is provided with one or more
flexible regions to reside within the one or more angled, curved or
bent regions of the outer member for transmitting torque to rotate
the cutting element while conforming to the angled configuration of
the outer member. The angled configuration of the outer member is
particularly beneficial in facilitating positioning of the cutting
element at the surgical site where there is a non-straight path in
the body from the entry opening to the surgical site. In such
cases, angled rotary tissue cutting instruments are usually better
suited to access the surgical site more easily and quickly, and
with less trauma to the patient, than are rotary tissue cutting
instruments in which the outer tubular member is longitudinally
straight. In many surgical procedures performed using rotary tissue
cutting instruments, the internal lumen of the inner tubular member
is used to transmit suction to the surgical site to aspirate
anatomical tissue and/or fluid through the inner member. In
addition, an annular gap or clearance between the internal diameter
of the outer member and the external diameter of the inner member
is commonly used as an irrigation passage to supply irrigation
fluid to the surgical site.
One design advantage in rotary tissue cutting instruments is to
minimize the external diametric size of the outer member to allow
introduction of the instrument in the patient's body through entry
openings as small as possible in size and/or to facilitate
advancement of the instrument to the surgical site with as little
trauma as possible to the patient. Another design advantage in
rotary tissue cutting instruments is to maximize the internal
diameter of the inner tubular member so that aspiration of tissue
and/or fluid through the inner member can be accomplished with
greater efficiency and with less risk of clogging. Yet a further
design advantage in rotary tissue cutting instruments is to
maintain an appropriate annular clearance between the internal
diameter of the outer tubular member and the external diameter of
the inner member to avoid jamming of the instrument and/or to
provide efficient flow of irrigation fluid between the outer and
inner members. In angled rotary tissue cutting instruments, it
would also be a design advantage to minimize the number of
structural components or parts required for the flexible region of
the inner member, thereby reducing manufacturing and material
costs, as well as reducing the risk of operational problems arising
from structural complexity and/or multiple structural components.
The foregoing design advantages must necessarily be balanced
against the need to maintain sufficient strength and rigidity in
the flexible inner members of angled rotary tissue cutting
instruments when transmitting torque via the flexible regions,
particularly considering that angled rotary tissue cutting
instruments must oftentimes be designed to operate at high
rotational speeds and to withstand the forces imposed when cutting
very hard or tenacious anatomical tissue.
Various designs previously proposed for the flexible regions in the
inner members of angled rotary tissue cutting instruments have
limited the extent to which the aforementioned design advantages
can be optimized in angled rotary tissue cutting instruments. Some
of the deficiencies associated with prior designs proposed for the
flexible regions in the inner members of angled rotary tissue
cutting instruments include increased radial thickness of the
annular wall of the inner tubular member along the flexible region
resulting in a larger external diameter and/or smaller internal
diameter for the inner member, structural complexity and/or the
need for multiple assembled structural parts to form the flexible
region, constriction of the internal diameter of the flexible
region when transmitting torque within an angled region of the
outer tubular member, longitudinal stretching of the flexible
region, and insufficient strength and rigidity in the flexible
region limiting the range of bend angles over which the flexible
region is able to effectively transmit torque. Designs for the
flexible regions of inner tubular members of angled rotary tissue
cutting instruments that result in the inner tubular member being
of larger external diametric size normally require that the angled
outer tubular member be of larger external diametric size in order
to rotatably receive the inner member while maintaining the
appropriate annular clearance between the outer and inner members.
Designs for the flexible regions of inner tubular members of angled
rotary tissue cutting instruments that result in the inner tubular
member having a smaller internal diameter or that result in
constriction of the internal diameter will typically have a
negative impact on the ability to aspirate tissue and/or fluid
through the inner tubular member. Designs for the flexible regions
of inner tubular members of angled rotary tissue cutting
instruments that involve structural complexity and/or multiple
assembled structural parts generally result in the inner tubular
member being of higher cost and at increased risk of operational
problems. Operational problems are also more likely to occur in
inner tubular members of angled rotary tissue cutting instruments
in which the design for the flexible region in the inner member
makes the flexible region prone to longitudinal stretching.
In some flexible inner tubular members of angled rotary tissue
cutting instruments, the flexible regions are formed of a plurality
of concentric spirals, typically an inner spiral, a middle spiral
and an outer spiral attached to one another at their ends. Each
spiral is formed by winding a flat strip of material, with
alternating spirals being wound in opposite rotational directions
about a central longitudinal axis of the inner member as
represented by U.S. Pat. No. 4,646,738 to Trott, U.S. Pat. No.
5,286,253 to Fucci and U.S. Pat. No. 5,540,708 to Lim et al. It has
also been proposed to provide shafts having flexible regions made
up of concentric coils of wound wire of circular cross-section,
rather than wound flat strips of material, as represented by U.S.
Pat. No. 5,437,630 to Daniel et al and U.S. Pat. No. 5,529,580 to
Kusunoki et al and by German Patent DE 3828478 A1. The radial
dimension or thickness of the annular wall of a flexible region
comprised of multiple concentric spirals or coils tends to be
substantial since it includes the individual thickness of each
spiral or coil. Flexible regions of this type tend to result in
flexible inner tubular members of larger external diametric sizes
requiring diametrically larger outer tubular members, and/or of
smaller internal diameters leading to reduced aspiration
capability. In addition, flexible inner tubular members having
these types of flexible regions will ordinarily be associated with
higher material costs due to the multiple structural components
involved and with higher manufacturing costs associated with
producing and assembling the different structural components. The
risk of operational problems may be greater due to the presence of
multiple structural components and increased structural complexity,
and the securement or attachment sites for the multiple spirals or
coils present the potential for structural failure.
Another design approach for the flexible regions in the flexible
inner tubular members of angled rotary tissue cutting instruments
involves a single continuous spiral or helical cut formed in an
inner tube, and one or more layers of spiral wrap disposed over the
cut region of the inner tube as represented by U.S. Pat. No.
6,533,749 B1 to Mitusina et al and U.S. Pat. No. 6,656,195 B2 to
Peters et al, and by United States Patent Application Publication
No. US2005/0090849 A1 to Adams. The one or more layers of spiral
wrap are each formed by winding a flat strip of material over the
cut region in the inner tube and attaching the ends of the strip to
the tube. The helical cut and the one or more layers of spiral wrap
are arranged so that their rotational direction or turn about a
central longitudinal axis of the inner member alternate in opposite
directions. The Peters et al patent discloses the helical cut in
the inner tube as having a dovetail pattern. The extent to which it
is possible to minimize the radial dimension or thickness of the
annular wall of a flexible region comprised of an inner tube and
one or more layers of spiral wrap over a cut region of the tube is
limited by the fact that the wall thickness of the inner tube and
the thickness of each layer of spiral wrap contribute cumulatively
to the radial dimension of the annular wall formed by the flexible
region. Furthermore, the inner tube and each spiral wrap are
separate structural components assembled during manufacture, giving
rise to issues of increased cost and structural complexity.
U.S. Pat. No. 7,338,495 B2 to Adams is an example of a flexible
region in a flexible inner tubular member of an angled rotary
surgical cutting instrument formed of a helical cut in an inner
tube, a layer of adhesive disposed over the cut region of the inner
tube, and a heat shrunk sleeve disposed over the cut region of the
inner tube and being bonded thereto by the adhesive. The helical
cut is formed in the inner tube in a stepped pattern. Again, the
radial thickness of the annular wall formed by the flexible region
is made up of the individual thicknesses of the inner tube wall,
the adhesive layer, and the wall of the sleeve. The flexible region
requires multiple parts or materials in addition to the inner tube,
and is still somewhat complicated from a manufacturing
standpoint.
Flexible regions have also been provided in the inner tubular
members of angled rotary tissue cutting instruments by forming
disconnected slots or openings in an inner tube as illustrated by
U.S. Pat. No. 5,152,744, 5,322,505 and 5,510,070 to Krause et al,
U.S. Pat. No. 5,620,415 to Lucey et al, and U.S. Pat. No. 5,620,447
to Smith et al. Each slot is filled with a pliable material in a
multi-step process carried out after the slots are formed. The
preferred slot configuration described in the Krause et al, Lucey
et al and Smith et al patents involves circumferentially
discontinuous slots disposed in parallel spaced relation, the slots
being arranged perpendicular to the longitudinal axis of the inner
tube.
U.S. Pat. No. 6,053,922 to Krause et al pertains to a flexible
shaft for reaming the medullary space in bones. In contrast to the
flexible inner members of angled rotary tissue cutting instruments,
the flexible shaft of Krause et al '922 is not shown to be
rotatably disposed within a rigid outer tubular member, and is
thusly not subject to the same design considerations as the inner
members of rotary tissue cutting instruments and of angled rotary
tissue cutting instruments in particular. In further distinction to
the flexible inner tubular members of angled rotary tissue cutting
instruments, the flexible shaft of Krause et al '922 is said to be
an elongated tubular member of substantial wall thickness. A
flexible inner tubular member of substantial wall thickness would
be undesirable in an angled rotary tissue cutting instrument
because it would result in a reduction in the internal diameter of
the inner member, which would reduce aspiration capability, and/or
it would require an outer member of larger external diameter to
accommodate the inner member, which would require larger size entry
openings in the patient's body for introduction of the instrument.
The tubular member of Krause et al '922 comprises a slot, said to
be of substantial width, extending spirally around the tubular
member in a pattern that forms pairs of complementary, mating
interlocking teeth and recesses in the tubular member that Krause
et al '922 relies on to transmit torque. The tooth and recess slot
pattern repeats without interruption, such that each complementary,
mating interlocking tooth and recess pair borders the next
complementary, mating interlocking tooth and recess pair. The slot
configuration thusly consists entirely of the configurations of the
teeth and recesses of the particular slot pattern, resulting in an
"unbound joint".
Despite the numerous different design approaches previously
proposed for the flexible inner members of angled rotary tissue
cutting instruments, it was not recognized until the present
invention that a flexible region comprising a cut formed in a
tubular body of the inner member with convoluted path areas between
non-convoluted connecting path segments of the cut would provide
numerous design advantages, including the advantages of design
simplicity, eliminating the need for the flexible region to include
an additional structure or layer of material over the cut region of
the tubular body or within the cut itself, appropriate rigidity and
torsional strength, resistance to stretching in the longitudinal
axial direction of the inner member, preservation of the integrity
of the internal diameter of the inner member, and the capability to
transmit torque within angled outer tubular members having a broad
range of bend angles.
SUMMARY OF THE INVENTION
The present invention is generally characterized in a flexible
inner member for being rotatably disposed within an angled outer
tubular member of a rotary tissue cutting instrument. The outer
tubular member includes a distal end, a longitudinal internal
passage, an open proximal end communicating with the passage, an
angled region between the distal and proximal ends, and an opening
in the distal end communicating with the internal passage. The
flexible inner member has a distal end, a proximal end, a tubular
body between the distal and proximal ends of the inner member, a
cutting element at the distal end of the inner member, and a
flexible region for being disposed within the angled region of the
outer tubular member. When the inner member is rotatably disposed
within the internal passage of the outer tubular member, the
cutting element is exposed from the opening in the outer tubular
member, and the flexible region is disposed within the angled
region to transmit torque to rotate the cutting element while
conforming to the configuration of the angled region. The tubular
body of the inner member has a central longitudinal axis and a
cylindrical wall having a wall thickness between external and
internal diameter surfaces of the cylindrical wall. The flexible
region comprises a convoluted or vortical cut in the tubular body
extending entirely through the wall thickness of the cylindrical
wall. The convoluted cut has a starting end on the tubular body and
has a terminating end on the tubular body. The convoluted cut
extends longitudinally along the tubular body and extends in a
rotational direction about the central longitudinal axis in a
forward direction of the convoluted cut from the starting end to
the terminating end. The convoluted cut includes a plurality of
convoluted or vortical path areas rotationally spaced about the
central longitudinal axis between the starting end and the
terminating end and in which the cut follows a convoluted or
vortical path or configuration, and a plurality of connecting path
segments in alternating sequence or succession with the convoluted
path areas between the starting end and the terminating end. The
connecting path segments extend rotationally along the tubular body
in the rotational direction of the cut about the central
longitudinal axis. The connecting path segments are devoid of
convoluted path areas and extend in the rotational direction at a
non-perpendicular angle to the central longitudinal axis.
The convoluted path areas are situated between a next preceding
connecting path segment and a next succeeding connecting path
segment in the forward direction of the cut. The convoluted path
followed by the cut in the convoluted path areas comprises a first
major curve of concave curvature extending in a lateral direction
away from the next preceding connecting path segment, a first minor
curve of concave curvature reverse from the curvature of the first
major curve and extending from the first major curve in the
opposite lateral direction toward the next preceding connecting
path segment, a second minor curve of concave curvature reverse
from the curvature of the first minor curve and extending from the
first minor curve in the lateral direction toward the next
preceding connecting path segment, and a second major curve of
concave curvature reverse from the curvature of the second minor
curve and extending from the second minor curve in the lateral
direction away from the next preceding connecting path segment to
join the next succeeding connecting path segment. The first minor
curve is within the second major curve and is spaced from the
second major curve in a direction radial to the second major curve.
The second minor curve is within the first major curve and is
spaced from the first major curve in a direction radial to the
first major curve.
The configuration of the cut in the convoluted path areas forms the
wall of the tubular body into a pair of complementary, mating and
interengaging, opposed first and second hook formations in the
convoluted path areas. The first hook formations have a concavely
curving body ending at a rounded tip. The second hook formations
have a concavely curving body ending at a rounded tip, the body of
the second hook formation being of reverse curvature from the body
of the first hook formation. The tip of each of the first and
second hook formations mates with the concave curvature of the body
of the opposed hook formation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded side view of an angled rotary tissue cutting
instrument.
FIG. 2 is a broken side view of a flexible region of a flexible
inner member of the angled rotary tissue cutting instrument.
FIG. 3 is a broken perspective view of a tubular body having a
convoluted cut therein comprising the flexible region of FIG.
2.
FIG. 4 is a broken, enlarged side view of the convoluted cut in the
tubular body.
DETAILED DESCRIPTION OF THE INVENTION
An angled rotary tissue cutting instrument 10 is depicted in FIG. 1
and comprises an elongate angled outer tubular member 12 and an
elongate flexible inner member 14 for being rotatably disposed
within the outer tubular member 12. The outer tubular member 12 has
a distal end 16 with an opening 18 therein in communication with
the internal passage 20 in the outer tubular member. The outer
tubular member 12 has a proximal length portion 22 terminating at
an open proximal end typically secured in an outer member hub 24
designed for engagement with a powered surgical handpiece (not
shown) in a conventional manner. The outer tubular member 12 is
provided with one or more angled, curved or bent regions 26 along
the length thereof, such that the outer tubular member 12 has an
angled configuration. Each angled region 26 in the outer tubular
member 12 defines a bend angle A corresponding to the angle defined
between length portions of the outer tubular member 12 that are
joined by the angled region. The outer tubular member 12, for
example, has a bend angle A defined between the central
longitudinal axis 28 of the proximal length portion 22 of the outer
member 12 and a central longitudinal axis 30 of a distal length
portion 32 of the outer member 12 which is joined to the proximal
length portion 22 by the angled region 26. The size and the
direction of the bend angle A can vary individually for each angled
region 26. The outer tubular member 12 illustrated in FIG. 1 has
one angled region 26 with a bend angle A extending in a downward
direction from proximal length portion 22.
As a result of its angled configuration, the outer tubular member
12 is not longitudinally straight along its length. However, the
outer tubular member 12 can initially be provided in a
longitudinally straight configuration, without the one or more
angled regions 26, and can be bent from the longitudinally straight
configuration in any suitable manner to obtain the angled
configuration desired for the outer tubular member. Accordingly,
bending the outer tubular member 12 from the longitudinally
straight configuration to the desired angled configuration will
involve bending the outer tubular member 12 as needed to obtain the
desired number of angled regions 26 at the desired location or
locations along the length of the outer tubular member and
extending in the desired direction or directions at the desired
bend angle or angles A. It should be appreciated that the outer
tubular member 12 can be bent from the longitudinally straight
configuration to the angled configuration with or without the
flexible inner member 14 disposed within the outer tubular member
12. The outer tubular member 12 is rigid in a longitudinally
straight configuration but is able to be bent to form the desired
angled region(s) when sufficient bending force is applied. The
outer tubular member 12 is or remains rigid after bending to form
the one or more angled regions.
The inner member 14 has a central longitudinal axis 33, a distal
end 34 provided with or formed as a cutting element 36, a proximal
length portion 38 terminating at a proximal end that is typically
secured in an inner member hub 40, and one or more flexible regions
42 between the cutting element 36 and the inner member hub 40. The
one or more flexible regions 42 impart flexibility to the inner
member that allows the inner member to bend along its central
longitudinal axis 33. When the inner member 14 is assembled with
the outer tubular member 12 to cut anatomical tissue, the inner
member 14 will extend through the outer member hub 24 and will be
rotatably disposed within the internal passage 20 of the outer
tubular member 12 with the cutting element 36 exposed from the
opening 18 in the outer member, with the one or more flexible
regions 42 disposed within the one or more angled regions 26 of the
outer member, and with the inner member hub 40 disposed proximally
of the outer member hub 24 for engagement with the powered surgical
handpiece. The powered surgical handpiece is operated in a
conventional manner to rotate the inner member 14 relative to and
within the outer tubular member 12, and the one or more flexible
regions 42 transmit torque to rotate the cutting element 36 while
conforming to the angled configuration of the outer tubular member
12. As the inner member 14 is rotated within the outer tubular
member 12, the cutting element 36 exposed from the opening 18 will
cut anatomical tissue contacted with the cutting element 36.
The inner member 14 comprises a cylindrical tubular body 43 coaxial
with the central longitudinal axis 33 and having an internal lumen
44 extending longitudinally within the tubular body. The tubular
body 43 preferably has an open end forming the proximal end of the
inner member 14 and preferably extends from the proximal end of the
inner member 14 to the cutting element 36, which is the case for
tubular body 43. Preferably, the tubular body 43 is an integral and
unitary or monolithic tube from the proximal end of the inner
member 14 to the cutting element 36, which is also the case for
tubular body 43. Accordingly, the flexible inner member 14 is a
flexible inner tubular member. As described further below, the one
or more flexible regions 42 are each formed by a convoluted or
vortical cut in the tubular body 43.
The cutting element 36 can have various cutting configurations
effective to cut anatomical tissue including the various cutting
configurations conventionally used for the inner members of rotary
tissue cutting instruments. The cutting element 36 can be a
structure that is hollow or provided with an interior cavity or
channel in communication with the lumen 44 of the tubular body 43.
The cutting element 36 can be a structure formed separate from and
attached to the tubular body 43. The distal end 34 of the inner
tubular member 14 can have an opening 46 therein in communication
with the internal lumen 44 of the inner member 14, and the opening
46 can communicate with the lumen 44 via the interior cavity or
channel in the structure that forms the cutting element 36. The
cutting configuration for the cutting element 36 can include one or
more cutting surfaces or edges along the periphery of the opening
46 as is the case for the cutting element 36 of the inner member 14
depicted in FIG. 1. The cutting surfaces or edges of the cutting
element 36 can be defined by cutting tooth formations, as is also
the case for the cutting element 36 of inner member 14. The cutting
surfaces or edges of the cutting element 36 can be defined by flute
formations as in a bur tip, for example.
The distal end 16 of the outer tubular member 12 can be provided
with or formed as a cutting element 48 that cooperates with the
cutting element 36 of the inner member 14 to cut anatomical tissue.
The cutting element 48 can have various cutting configurations
effective to cut anatomical tissue in cooperation with the cutting
element 36, and the various cutting configurations conventionally
used for the outer members in rotary tissue cutting instruments can
be used for the cutting configuration of the cutting element 48.
The cutting configuration for the cutting element 48 can include
one or more cutting surfaces or edges along the periphery of the
opening 18 as is the case for the cutting element 48 of the outer
tubular member 12 depicted in FIG. 1. The cutting surfaces or edges
of the cutting element 48 can be defined by cutting tooth
formations, as is also the case for the cutting element 48.
Typically, the cutting elements 36 and 48 cooperate to cut
anatomical tissue as a result of rotation of the one or more
cutting surfaces or edges of the cutting element 36 past the one or
more cutting surfaces or edges of the cutting element 48.
As the cutting element 36 is rotated, the opening 46 in the inner
member 14 will come into alignment with the opening 18 in the outer
tubular member 12, allowing anatomical tissue and/or fluid to enter
the lumen 44 of the inner member 14 through the aligned openings 18
and 46. Through the application of vacuum or suction to the lumen
44, typically via a connection at a proximal end of the instrument
10 in a conventional manner, the lumen 44 can serve as an
aspiration passage by which suction is applied at the surgical site
via the aligned openings 18 and 46 and by which fluid and/or
anatomical tissue is/are drawn into the lumen 44 through the
aligned openings 18 and 46 for evacuation through the instrument
10.
In order for the inner member 14 to rotate within the outer tubular
member 12 without jamming, an appropriate annular clearance or gap
is present between the internal diameter of the outer tubular
member 12 and the external diameter of the inner member 14 when the
members 12 and 14 are assembled to cut tissue. The annular
clearance or gap between the outer and inner members 12 and 14 can
serve as an irrigation passage by which irrigation fluid supplied
to the annular clearance, typically from a proximal end of the
instrument 10, is conveyed distally and released at the surgical
site through the opening 18 in the outer tubular member 12.
The inner member 14 can have a single flexible region 42 of
sufficient length and at the appropriate location to reside in and
conform to the configuration of one or more angled regions 26 in
the outer tubular member 12. The inner member 14 can have a
plurality of flexible regions 42, each of sufficient length and at
the appropriate location to reside in and conform to the
configuration of a corresponding angled region 26 in the outer
tubular member 12. Each flexible region 42 can be disposed adjacent
and/or between rigid or non-flexible length segments of the tubular
body 43. The inner member 14 is an example of one having a single
flexible region 42 disposed between rigid or non-flexible length
segments 50 and 52 of the tubular body 43, the single flexible
region 42 being located appropriately along the length of the inner
member 14 to reside within the single angled region 26 in the outer
tubular member 12 and being of sufficient length to conform to the
configuration of the single angled region 26 when the inner member
14 is assembled with the outer member 12 to cut anatomical tissue.
The length segment 50 of the tubular body 43 is part of the
proximal length portion 38, which will be disposed within the
proximal length portion 22 of the outer member 12 when the inner
member is assembled with the outer member to cut anatomical tissue.
The length segment 52 of the tubular body 43 may thusly be
considered a distal length portion and will be disposed within the
distal length portion 32 of the outer member 12 when the inner and
outer members are assembled to cut anatomical tissue.
The flexible region 42, which is best depicted in FIGS. 2-4,
comprises a convoluted or vortical cut 56 formed in the tubular
body 43 of the inner member 14. As best shown in FIG. 3, the
tubular body 43 has a cylindrical wall with an external diameter
surface 53, an internal diameter surface 54 defining the lumen 44,
and a radial wall thickness 55 between the external and internal
diameter surfaces. Prior to the convoluted cut 56 being formed
therein, the wall of the tubular body 43 along the flexible region
42 and along the length segments 50 and 52 is a rigid, integral and
unitary, one piece or monolithic, solid, annular wall coaxial with
the central longitudinal axis 33. The convoluted cut 56 extends
through the entire wall thickness 55 of the cylindrical wall of the
tubular body 43. The convoluted cut 56 has a starting end 58 on the
tubular body 43 as seen in FIGS. 2 and 3, and has a terminating end
60 on the tubular body 43 as seen in FIGS. 2 and 4. The cut 56
extends longitudinally along the tubular body 43 and extends in a
rotational direction about the central longitudinal axis 33 in a
forward direction of the cut 56, the forward direction being the
direction of advancement or forward progress followed by the path
of the cut from the starting end 58 to the terminating end 60. The
cut therefore follows a winding path from the starting end to the
terminating end. Looking in the forward direction of cut 56 from
the starting end 58 toward the terminating end 60, the rotational
direction for cut 56 is in a counterclockwise direction about the
axis 33 from the starting end 58 to the terminating end 60.
However, it should be appreciated that the cut could rotate in a
clockwise rotational direction about the axis 33 in the forward
direction from the starting end 58 toward the terminating end 60.
The convoluted cut 56 has a plurality of convoluted or vortical
path areas 61 between the starting end 58 and the terminating end
60 within which the cut 56 follows a convoluted or vortical path or
configuration as explained further below. In the case of convoluted
cut 56, the terminating end 60 is located on the tubular body 43
distally of the starting end 58, such that the forward direction of
the cut 56 is in the distal direction along the inner member 14. It
should be appreciated, however, that the starting and terminating
ends can be reversed, such that the end 60 can be the starting end
for the cut 56 and the end 58 can be the terminating end for the
cut 56, in which case the forward direction of the cut is in the
proximal direction along the inner member 14.
The convoluted cut 56 comprises the plurality of convoluted path
areas 61, which are rotationally spaced about the central
longitudinal axis 33, and a plurality of connecting path segments
64 in alternating sequence or succession with the convoluted path
areas 61 between the starting end 58 and the terminating end 60.
The convoluted cut 56 is continuous within and through each
convoluted path area 61, there being no breaks or gaps in the cut
56 in the convoluted path areas 61. The convoluted cut 56 is one in
which the entire cut 56 is continuous from its starting end 58 to
its terminating end 60, there being no breaks or gaps in the cut 56
from the starting end to the terminating end.
The connecting path segments 64 for the convoluted cut 56 comprise
a starting connecting path segment 64a adjacent the starting end
58, a terminating connecting path segment 64b adjacent the
terminating end 60, and a plurality of intermediate connecting path
segments 64c between the starting and terminating connecting path
segments 64a and 64b. The connecting path segments 64 extend
rotationally about the central longitudinal axis 33 in the
rotational direction of the cut 56, i.e. counterclockwise in the
case of convoluted cut 56. The connecting path segments 64 extend
rotationally about the central longitudinal axis 33 at a
non-perpendicular angle B to the central longitudinal axis 33. As
seen in FIG. 2, the connecting path segments 64 extend rotationally
along the tubular body 43 at an acute angle B to a plane P1
perpendicular to the central longitudinal axis 33. In the case of
convoluted cut 56, the connecting path segments 64 extend in the
forward direction of the cut 56 with an angle or slant toward the
proximal end or direction of the inner member 14 and toward the
starting end 58 of the cut 56. The connecting path segments 64 are
non-convoluted or devoid of convoluted path areas 61. The
connecting path segments 64 may each follow a linear course or path
that is disposed in a plane that defines angle B with the plane P1.
The connecting path segments 64 are of the same length between the
convoluted path areas 61 such that the convoluted path areas 61
repeat at uniform intervals along the cut 56.
The starting connecting path segment 64a extends rotationally along
the tubular body 43 in the forward direction of the cut 56 to a
convoluted path area 61 situated between the starting connecting
path segment 64a and a first intermediate connecting path segment
64c, the first intermediate connecting path segment 64c being the
connecting path segment 64 that next succeeds or follows the
starting connecting path segment 64a in the forward direction of
the cut 56. Each intermediate connecting path segment 64c extends
rotationally along the tubular body 43 in the forward direction of
the cut 56 from a convoluted path area 61 to a next succeeding
convoluted path area 61. The terminating connecting path segment
64b extends rotationally along the tubular body 43 in the forward
direction of the cut 56 from a convoluted path area 61 situated
between the terminating connecting path segment 64b and a last
intermediate connecting path segment 64c, the last intermediate
connecting path segment 64c being the connecting path segment 64
that next precedes or comes before the terminating connecting path
segment 64b. In other words, the last intermediate connecting path
segment 64c is the connecting path segment 64 that next follows or
comes after the terminating connecting path segment 64b in the
reverse or rearward direction of the cut 56, the reverse direction
of the cut 56 being in the opposite direction from the forward
direction of the cut 56.
The convoluted cut 56 is an example of one in which the starting
end 58 is a starting point of the cut 56 situated at the beginning
of a convoluted path area 61 that next precedes the starting
connecting path segment 64a and from which the starting connecting
path segment 64a extends in the forward direction of the cut to a
next succeeding convoluted path area 61. In this case, the first
convoluted path area 61 of the cut 56 is the one at the starting
end 58, and the starting connecting path segment 64a extends in the
forward direction of the cut 56 from the first convoluted path area
to the next succeeding convoluted path area. However, it should be
appreciated that the convoluted cut 56 can be without a convoluted
path area at the starting end 58 and that the starting end 58 can
be a starting point of the cut 56 that begins the starting
connecting path segment 64a. In this case, the convoluted path area
61 that next succeeds the starting connecting path segment 64a and
to which the starting connecting path segment 64a extends in the
forward direction of the cut 56 from the starting end 58 will be
the first convoluted path area of the cut. The convoluted cut 56 is
also an example of one in which the terminating end 60 is a
terminal point of the cut 56 situated at the end of a convoluted
path area 61 that next succeeds the terminating connecting path
segment 64b and to which the terminating connecting path segment
64b extends in the forward direction of the cut 56 from a next
preceding convoluted path area 61. In this case, the last
convoluted path area 61 of the cut 56 is the one at the terminating
end 60. It should be appreciated, however, that the convoluted cut
56 can be without a convoluted path area at the terminating end 60
and that the terminating end 60 can be a terminal point of the cut
56 at an end of the terminating connecting path segment 64b. In
this case, the convoluted path area 61 that next precedes the
terminating connecting path segment 64b and from which the
terminating connecting path segment 64b extends in the forward
direction of the cut to the terminating end 60 will be the last
convoluted path areas of the cut 56. It should also be appreciated
that the convoluted path area containing the starting end 58 and/or
the terminating end 60 can be partial convoluted path areas in
which the cut 56 follows less than the entire convoluted path
followed by the cut in the other convoluted path areas 61.
The convoluted path or configuration defined or followed by the cut
56 in the convoluted path areas 61 is best described with reference
to FIGS. 3 and 4 and includes an entering convoluted or vortical
path portion 66a and an exiting convoluted or vortical path portion
66b. The entering convoluted path portion 66a is the path or
configuration defined or followed by the cut 56 in the forward
direction after entering the convoluted path area 61 from a next
preceding connecting path segment 64, except that the convoluted
path area that contains the starting end 58 is not preceded by a
connecting path segment. The exiting convoluted path portion 66b is
the path or configuration defined or followed by the cut 56
continuing in the forward direction from the entering convoluted
path portion 66a to the next succeeding connecting path segment 64
upon exiting the convoluted path area 61, except that the
convoluted path area that contains the terminating end 60 is not
succeeded by a connecting path segment. The exiting convoluted path
portion 66b is an inverted mirror image of the entering convoluted
path portion 66a, and the convoluted path portions 66a and 66b
together make up the entire or complete convoluted path or
configuration followed by the cut 56 in the convoluted path area
61. However, as pointed out above, the convoluted path areas that
contain the starting and/or terminating ends can have partial
convoluted configurations. For example, the convoluted path area
containing the starting end 58 can have an abbreviated or partial
entering convoluted path portion, and the convoluted path area
containing the terminating end 60 can have an abbreviated or
partial exiting convoluted path portion.
The entering convoluted path portion 66a is a multi-directional,
variably or multiply curving path or configuration comprising a
first or entering path major curve 68a extending from the
connecting path segment 64 that next precedes the convoluted path
area 61, and a first or entering path minor curve 70a of reverse
curvature to the major curve 68a and extending from the major curve
68a to the exiting convoluted path portion 66b. The exiting
convoluted path portion 66b is a multi-directional, variably or
multiply curving path or configuration comprising a second or
exiting path minor curve 70b of reverse curvature to the first
minor curve 70a and extending from the first minor curve 70a to a
second or exiting path major curve 68b of the exiting convoluted
path portion 66b. The major curve 68b of the exiting convoluted
path portion 66b is of reverse curvature to the minor curve 70b and
extends from the minor curve 70b to the connecting path segment 64.
The first major curve 68a extends or curves in a lateral direction
away from the next preceding connecting path segment 64 with a
concave curvature, and the first minor curve 70a extends or curves
from the first major curve 68a in the opposite lateral direction
toward the next preceding connecting path segment 64 with a concave
curvature opposite or reverse from the concave curvature of the
first major curve 68a. The first major curve 68a is generally
C-shaped or U-shaped in configuration with a mid-section between a
pair of spaced apart sides. As best seen in FIGS. 3 and 4, the
first major curve 68a includes an inner side 72a joined to, merging
or continuous with the next preceding connecting path segment 64,
and an outer side 73a joined to, merging or continuous with the
first minor curve 70a. The first major curve 68a has a span or
width between the inner and outer sides 72a and 73a. The first
minor curve 70a is generally C-shaped or U-shaped in configuration
with a mid-section between a pair of spaced apart sides, but has a
more pronounced curvature than and curves in the opposite or
reverse direction from the C-shaped or U-shaped configuration of
the first major curve 68a. The first minor curve 70a has an outer
side 74a joined to, merging or continuous with the outer side 73a
of the first major curve 68a and has an inner side 75a continuous
with the second minor curve 70b. The first major curve 68a has a
major radius of curvature R1, and the first minor curve 70a has a
minor radius of curvature R2 smaller than the major radius of
curvature R1 as depicted in FIG. 4. The first minor curve 70a has a
span or width between the outer and inner sides 74a and 75a that is
less than the span of the first major curve 68a. The entering
convoluted path portion 66a has a width W in a direction parallel
to central longitudinal axis 33, the width W being the distance
between plane P2 perpendicular to axis 33 and tangential to inner
side 72a of major curve 68a and plane P3 parallel to plane P2 and
tangential to outer side 74a of minor curve 70a.
The multi-directional, variably or multiply curving path or
configuration of the entering convoluted path portion 66a is one in
which the path of the cut 56 in the forward direction curves or
extends in a lateral direction away from the next preceding
connecting path segment 64 with a relatively gentle concave
curvature (first major curve 68a) to an offset position spaced
laterally from the next preceding connecting path segment 64, and
then curves or extends with a reverse, relatively sharp or more
pronounced concave curvature and in the opposite lateral direction
(first minor curve 70a) toward the next preceding connecting path
segment 64 to a second offset position mid-way between the first
offset position and the next preceding connecting path segment 64.
The lateral direction in which the first major curve 68a curves or
extends away from the next preceding connecting path segment 64 is
transverse to the next preceding and next succeeding connecting
path segments and is the lateral direction toward the next
succeeding connecting path segment 64. The opposite lateral
direction in which the first minor curve 70a curves or extends from
the first major curve 68a is transverse to the next preceding and
next succeeding connecting path segments and is the lateral
direction away from the next succeeding connecting path segment 64.
The lateral direction and/or the opposite lateral direction can be
perpendicular to the next preceding and next succeeding connecting
path segments. The lateral direction that the first major curve 68a
curves or extends away from the next preceding connecting path
segment 64 is longitudinal along the tubular body 43 in the
direction toward the terminating end 60 of the cut 56 and toward
the distal end or direction of the inner member 14. The opposite
lateral direction in which the first minor curve 70a curves or
extends from the first major curve 68a is longitudinal along the
tubular body 43 in the direction toward the starting end 58 of the
cut 56 and toward the proximal end or direction of the inner member
14. The lateral direction and/or the opposite lateral direction may
be longitudinal along the tubular body 43 parallel with the central
longitudinal axis 33 or at an oblique angle to the central
longitudinal axis 33.
The path or configuration of the exiting convoluted path portion
66b is the same multi-directional, variably or multiply curving
path or configuration as the entering convoluted path portion 66a
but is an inverted mirror image of the entering convoluted path
portion 66a. The second minor curve 70b curves or extends laterally
from the first minor curve 70a with a concave curvature opposite or
reverse from the concave curvature of the first minor curve 70a and
in the same lateral direction that the first minor curve 70a
extends from the first major curve 68a, i.e. toward the next
preceding connecting path segment 64 and away from the next
succeeding connecting path segment 64. The second major curve 68b
extends or curves laterally from the second minor curve 70b with a
concave curvature opposite or reverse from the concave curvature of
the second minor curve 70b and in the same lateral direction that
the first major curve 68a extends from the next preceding
connecting path segment, i.e. toward the next succeeding connecting
path segment 64 and away from the next preceding connecting path
segment 64, to join the next succeeding connecting path segment.
The second minor curve 70b is generally C-shaped or U-shaped in
configuration like the first minor curve 70a but is curved in the
opposite or reverse direction from the C-shaped or U-shaped
configuration of the first minor curve 70a. The second minor curve
70b is thusly curved in the same direction as the first major curve
68a. The second minor curve 70b has an outer side 74b, an inner
side 75b joined to, merging or continuous with the inner side 75a
of the first minor curve 70a, and a span between the outer and
inner sides 74b and 75b as described for the first minor curve 70a.
The second major curve 68b is generally C-shaped or U-shaped in
configuration like the first major curve 68a but is curved in the
opposite or reverse direction from the C-shaped or U-shaped
configuration of the first major curve 68a. The second major curve
68b is thusly curved in the same direction as the first minor curve
70a. The second major curve 68b has an outer side 73b joined to,
merging or continuous with the outer side 74b of the second minor
curve 70b, an inner side 72b joined to, merging or continuous with
the next succeeding connecting path segment 64, and a span between
the inner and outer sides 72b and 73b as described for the first
major curve 68a. The second major curve 68b has the radius of
curvature R1, and the second minor curve 70b has the radius of
curvature R2. In the convoluted path areas 61, the radius of
curvature R2 is or is about 60% of the radius of curvature R1. The
exiting convoluted path portion 66b has the same width W as the
entering portion 66a but between parallel planes perpendicular to
axis 33 and respectively tangential to the inner side 72b of second
major curve 68b and to the outer side 74b of second minor curve
70b.
The first minor curve 70a is arranged within or inside of the
second major curve 68b, with the curves 70a and 68b being in spaced
relation and the span of the first minor curve 70a fitting within
the span of the second major curve 68b. The first minor curve 70a
is spaced from the second major curve 68b in a direction radial to
the second major curve 68b. The second minor curve 70b is arranged
within or inside of the first major curve 68a, with the curves 70b
and 68a being in spaced relation and the span of the second minor
curve 70b fitting within the span of the first major curve 68a. The
second minor curve 70b is similarly but oppositely spaced from the
first major curve 68a in a direction radial to the first major
curve 68a. The arrangement and spaced relationship between curves
70b and 68a is the same as that for curves 70a and 68b, except that
curves 70b, 68a are of opposite or reverse curvature from the
curves 70a, 68b. The conjoined inner sides 75a, 75b of the first
and second minor curves 70a, 70b are disposed mid-way or
substantially mid-way between the outer sides 74a, 74b of the first
and second minor curves 70a, 70b. The conjoined inner sides 75a,
75b of the first and second minor curves 70a, 70b are disposed
mid-way or substantially mid-way between the conjoined inner side
72a/next preceding connecting path segment 64 and the conjoined of
inner side 72b/next succeeding connecting path segment 64. The
first major curve 68a overlaps the outer side of the second major
curve 68b, and the second major curve 68b overlaps the outer side
of the first major curve 68a. The first and second minor curves 70a
and 70b are arranged side by side. The width W of the entering path
portion 66a partly overlaps the width W of the exiting path portion
66b. The widths of both the entering and exiting path portions are
between the next preceding and next succeeding connecting path
segments.
The path or configuration of the cut 56 in the convoluted path
areas 61 thusly involves two major concave curves, i.e. the first
major curve 68a and the second major curve 68b, that curve in
opposite directions to one another, and two minor concave curves,
i.e. the first minor curve 70a and the second minor curve 70b, that
curve in opposite directions to one another between the major
concave curves, and wherein each curve is followed or next
succeeded by one of reverse curvature. In the convoluted path areas
61, the path of cut 56 in the forward direction takes a first,
relatively wide curve or bend of relatively gentle concave
curvature (first major curve 68a) from the next preceding
connecting path segment 64 in the distal direction of the inner
member 14, followed by a first, relatively narrower curve or bend
of relatively sharper concave curvature (first minor curve 70a) in
the proximal direction of the inner member 14 and of reverse
curvature from the first, relatively wide curve, followed by a
second, relatively narrower curve or bend of the relatively sharper
concave curvature (second minor curve 70b) in the proximal
direction and of reverse curvature from the first, relatively
narrower curve, followed by a second, relatively wide curve or bend
of the relatively gentle concave curvature (second major curve 68b)
in the distal direction and of reverse curvature from the second,
relatively narrower curve to join the next succeeding connecting
path segment 64.
Each convoluted path area 61 is joined to the next succeeding
convoluted path area 61 by a connecting path segment 64. Each
convoluted path area 61 is rotationally spaced from the next
preceding convoluted path area 61 in the rotational direction of
the cut 56 about the central longitudinal axis 33 of the tubular
body 43. In addition, each convoluted path area 61 is offset or
spaced longitudinally from the next preceding convoluted path area.
In the case of convoluted cut 56, each convoluted path area 61 is
longitudinally offset from the next preceding convoluted path area
61 in a longitudinal direction that is toward the terminating end
60 of the cut 56 and toward the distal end or direction of the
inner member 14. Each connecting path segment 64 is offset or
spaced longitudinally from the next preceding connecting path
segment 64 in the longitudinal direction that is toward the
terminating end 60 and toward the distal end or direction of the
inner member 14. Also, the connecting path segments 64 are in
parallel to one another along the tubular body 43.
The convoluted cut 56 can be formed in the tubular body 43 in any
suitable manner, preferably by laser cutting the tubular body 43.
The radial dimension or thickness of the annular wall of the inner
tubular member 14 along the flexible region 42 is the same as the
wall thickness 55 of the tubular body 43 along the length portion
thereof that is formed with the cut 56, which is the same as the
wall thickness of the tubular body 43 along the solid, rigid, uncut
segments 50, 52.
In one illustrative referred embodiment, the radius of curvature R1
is or is about 0.02 inch; the radius of curvature R2 is or is about
0.012 inch; the width W is or is about 0.04 inch; the angle B is or
is about 20.degree.; the terminating end 60 of the cut 56 is or is
about 0.50 inch from the distalmost end surface of the cutting
element; the length of the cut region of the tubular body 43 from
the starting end 58 to the terminating end 60 of the cut 56 is or
is about 1.50 inches; and there are three convoluted path areas 61
in each complete, i.e. 360.degree., rotational turn or revolution
of the cut 56 about the central longitudinal axis 33.
The configuration of convoluted cut 56 in the convoluted path areas
61 forms the wall of tubular body 43 into a pair of complementary,
mating and interengaging, opposed first and second hook formations
78a and 78b in the convoluted path areas 61. The first hook
formations 78a are all disposed on one side of the convoluted cut
56, and the second hook formations 78b are all disposed on the
opposite side of the cut 56. The first hook formation 78a is
generally C-shaped or J-shaped in configuration comprising a flared
neck 80a and a concavely curved body 82a extending from the neck to
a rounded tip 84a. The wider part of the neck 80a merges integrally
with the solid portion of the wall of the tubular body 43 that lies
between successive rotational turns or revolutions of the cut 56
about the tubular body 43. The neck 80a is defined between the
first major curve 68a and the next succeeding connecting path
segment 64. The curved body 82a is defined between the first minor
curve 70a and the second major curve 68b. The curved body 82a has a
longer outer edge of concave curvature along second major curve 68b
and a shorter inner side edge of concave curvature along first
minor curve 70a, the outer and inner side edges having the same
direction of curvature. The tip 84a is defined by the second minor
curve 70b between the outer and inner side edges. The second hook
formation 78b has the same configuration as the first hook
formation 78a but is an inverted mirror image of the first hook
formation 78a. The second hook formation 78b includes a flared neck
80b, the wider part of which merges integrally with the solid
portion of the tubular body wall that lies between successive
rotational turns or revolutions of the cut 56 but on the opposite
side of the cut 56 from the neck 80a of first hook formation 78a.
The hook formation 78b includes a concavely curved body 82b
extending from the neck 80b to a rounded tip 84b. The neck 80b is
defined between the second major curve 68b and the next preceding
connecting path segment 64. The curved body 82b is defined between
the first major curve 68a and the second minor curve 70b. The
curved body 82b has a longer outer side edge of concave curvature
along first major curve 68a and a shorter inner side edge of
concave curvature along second minor curve 70b. The outer and inner
side edges of the body 82b have the same direction of curvature,
which is reverse from the direction of curvature of the outer and
inner side edges of body 82a. The tip 84b is defined by the first
minor curve 70a between the outer and inner side edges of the body
82b. The curved body 82a of hook formation 78a curves with a
clockwise rotation from the neck 80a in the direction of the
starting end 58 of the cut 56 and toward the proximal end or
direction of the inner member 14. The curved body 82b of hook
formation 78b curves with a clockwise rotation from the neck 80b in
the direction opposite or reverse from the hook formation 78a and,
therefore, the body 82b curves in the direction of the terminating
end 60 of the cut 56 and toward the distal end or direction of the
inner member 14. The body 82a of hook formation 78a curves or curls
over the tip 84b of hook formation 78b, and the body 82b of hook
formation 78b curves or curls over the tip 84a of hook formation
78a in a mating or interengaging fit. The tip 84a of hook formation
78a is mates within the cavity or recess defined by the concave
curvature of hook formation 78b and is thusly received between the
tip 84b and the neck 80b/body 82b of the hook formation 78b.
Conversely, the tip 84b of hook formation 78b mates with the cavity
or recess defined by the concave curvature of hook formation 78a
and is received between the tip 84a and the neck 80a/body 82a of
hook formation 78a. The tip of each hook formation thusly fits and
mates with the concave curvature of the opposed hook formation. The
hook formations 78a are all unified to one another via the wall of
the tubular body 43 disposed on the same side of the cut 56 as the
hook formations 78a. The hook formations 78b are all unified to one
another via the wall of the tubular body 43 disposed on the
opposite side of the cut 56 from the hook formations 78a. The
connecting path segments 64 of the convoluted cut 56 are devoid of
convoluted path areas 61 and, therefore, are without hook
formations 78a, 78b, such that each pair of mating hook formations
78a and 78b is rotationally spaced from the next succeeding pair of
mating hook formations about the central longitudinal axis 33 of
the tubular body 43. The hook formations 78a have a width equal to
the width W of the exiting convoluted path portions 66b, and the
hook formations 78b have a width equal to the width W of the
entering convoluted path portions 66a.
The cut 56 can be considered "vortical" in the sense that the hook
formations 78a, 78b and the path of the cut in the convoluted or
vortical path areas 61 are characterized by shapes that resemble a
"vortex", i.e. a curving, whirling or swirling shape that forms or
defines a cavity toward which something subject to its action is
drawn. In each convoluted or vortical path area 61, the vortical
path portions 66a, 66b and hook formations 78a, 78b have shapes
that resemble vortices rotating in a clockwise direction. The
entering path portion 66a rotates in a clockwise direction from the
next preceding connecting path segment and the exiting path portion
66b rotates in the clockwise direction from the next succeeding
connecting path segment. The first hook formations 78a rotate in
the clockwise direction from the necks 80a, and the second hook
formations 78b rotate in the clockwise direction from the necks
80b. Furthermore, each hook formation 78a, 78b defines a cavity or
recess into which the opposing hook formation is drawn.
The flexible region 42 has numerous advantages including, but not
limited to, appropriate rigidity and torsional strength, the
ability to transmit torque at bend angles of up to 90.degree.,
greater resistance to stretching in the longitudinal direction of
the inner member 14, and preservation of the integrity of the
internal diameter of the tubular body 43 when transmitting torque
during rotation of the inner member 14 within the angled outer
tubular member 12. The flexible region 42 has the further advantage
of not requiring any additional structural component(s) and/or
material(s) over or within the convoluted cut in order to operate
effectively as the flexible region for an inner member of an angled
rotary tissue cutting instrument. An additional advantage is that
the annular wall thickness of the inner member 14 along the
flexible region 42 can be better minimized in order to better
minimize the external diameter of the inner member and/or to better
maximize the internal diameter of the inner member. Also,
eliminating the need for additional structural components and/or
materials presents the advantage of allowing the flexible region 42
to be produced at lower cost and with greater structural simplicity
for a reduced risk of operational problems. Although the flexible
region 42 does not require any additional structural component(s)
over the convoluted cut, it is possible to provide a very
thin-walled sleeve or sheath over the cut region of the tubular
body while retaining the aforementioned advantages. The flexible
region 42 is especially well-suited for use with an angled outer
tubular member 12 having a bend angle A of up to 90.degree..
Inasmuch as the present invention is subject to many variations,
modifications and changes in detail, it is intended that all
subject matter discussed above or shown in the accompanying
drawings be interpreted as illustrative only and not be taken in a
limiting sense.
* * * * *